This section is intended to introduce the reader to various aspects of art that may be related to various aspects of the present invention, which are described and/or claimed below. This discussion is believed to be helpful in providing the reader with background information to facilitate a better understanding of the various aspects of the present invention. Accordingly, it should be understood that these statements are to be read in this light, and not as admissions of prior art.
As will be appreciated, oil and natural gas have a profound effect on modern economies and societies. Indeed, devices and systems that depend on oil and natural gas are ubiquitous. For instance, oil and natural gas are used for fuel in a wide variety of vehicles, such as cars, airplanes, boats, and the like. Further, oil and natural gas are frequently used to heat homes during winter, to generate electricity, and to manufacture an astonishing array of everyday products.
In order to meet the demand for such natural resources, companies often invest significant amounts of time and money in searching for and extracting oil, natural gas, and other subterranean resources from the earth. Particularly, once a desired resource is discovered below the surface of the earth, drilling and production systems are often employed to access and extract the resource. These systems may be located onshore or offshore depending on the location of a desired resource. Once the natural resource is extracted, it is generally transported to processing locations, such as refineries. The transportation of these resources is accomplished through a system of pipelines, which are controlled through various types of valves located at different points throughout the system.
One type of valve system used to isolate a section of pipeline and the fluid within the pipeline is referred to as a “double block and bleed” system. Such isolation is used to prevent contamination of the fluid by preventing contact with other fluids, and/or to meet regulatory safety requirements for valve and pipeline maintenance. Older designs for a double block and bleed system typically use two separate in-line valves having a section of pipe, or spool piece, between them. When both valves were shut off, a bleed valve was used to drain the spool and ensure seal integrity. This two valve system was superceded by a single double-seated valve, often referred to as a “double block and bleed” valve.
A double block and bleed valve is capable of sealing both upstream and downstream from the valve, and the valve body itself acts as the spool piece between the seals. The double block and bleed valve provides some advantages over a traditional two valve block and bleed system, such as ease and speed of operation, low maintenance requirements, and improved resistance to leaks. Such double block and bleed valves, or other valves used in the transportation system, may be formed from different metals or materials, such as a steel valve body, a cast iron valve plug, a steel valve stem, and so forth. The use of these different materials may introduce challenges in manufacturing that may affect performance once the valve is placed into service.